Testing machine



Nav. 17, 1925.

J. G. COFFIN .TESTING MACHINE Filed Sept. l, 19224 4 Sheets-Sheet 1 y vwentoz f JosEPH G. Cos'rm,

Nov. 17, 1925. l 1,561,970

J. G. coFFlN TESTING MACHINE y Filed Sept. l. 1922 4 Shee'LAS-Sheet 2 JOSEPH G. Con-m.

5in/vanto@ I @51g Ma btofvvuu A l J. G. col-'FIN TESTING MACHINE Filed sept. 1, 1922- 4 sheets-sheet s Nov. 17, 1925. I 1,561,970

wuantoz JOSEPH G.Co rrm @313m www,

Patented' Nov. 17, 1925.

UNITED STATES' PATENT- OFFICE.

v:rosnrn e.. corrris, or HEMPSTEAD, NEW Yonx, AssieNon fro MORGAN a WRIGHT,

OFDETROIT, MICHIGAN; CORPORATION F MICHIGAN.

'rEs'rrNeMAcmNn Application led September T o all whom/.it may concern.'

Be it known `that I, Josnrrr G.- CorrrN,

' a citizen of the United States, and residing at Hempstead, Long Island, county of Nassau, and State of New York, havein- 'i vented certain new and useful- Improvepensive,

ments in Testing Machines, of lowingis afull, clear, and tion.

'This invention relates to testing machines which the folexact descripmeasuring or and more particularly to a closed hydraulic elastic system in which the pressures developedr by an applied force are converted. into motion of. a, pointer or equivalent deviceI` for reading or recording the stresses applied to a specimen.

Heretofore, so far as I am aware, testing machines have utilized mechanical instrumentalities between an applied force and a gag l appliedc stresses to Generally, these old t ployed in mechanica forces to of error, are' slow,.I is necessary'.

proposed b ut ina form open toone or more serious objections preventing tion. v

general adop- Tlie present invention is radically different and -aims to provide between the applied force and an indicator elastic hydraulic system to the applicationjof a force,

orfscale, 'a closed instantly responsive which is without friction, which multipliessmall and invisible motion many vtimes---rendering it measurable and recordable-which requires no external springs-the restoring force being in the elastic structure of a device constituting 'part of thel system, v practicalpurposes, and which law exactly Within a given construction.

at least to .allv obeys Hookes the designed capacity'of The hydraulic system' is the essence of simplicity, extremely sensi- -tive and accurate, foolproof, 1 ated by even the most ally appears to be a long so atum. v

may be operignorant, and generught. desiderlVitli the illustrated embodiments in mind and without intention to limit more than` is required by the prior art,.the be said Ato consist primarily .1

' container offering no, error-1 invention may n a collapsible ntroducing re-j 'A pointer, device, may

the curled tub recording on a chart, free'end' of the tube.

1 1922; serial No. 585,612.

sista'nce to attempted change of its' volumetric capacity and introducing no error by the liiegligible change thereof thatmay occur, in. combination with a conduit extending great or sma nally bent tube, preferably; known Bourdon gage type a from the container any distancell-to a curled or. longitudiof the wellanchored and the other end free to move.

hand, mirror, or other 'suitable be attached to the free end of e for indicating on a'.Y dial, or.

the deflection of the .The free end of the tube is' moved or deflected indirect proportion to the change 1n the pressure within the system,

which change results 'from the application of a force or stre to the cushioned or shiftable end or IWall portionof thegcollapsiblel container.v

The invention 1s illustrated diagrammatically iny its particular application to a form of machine suitable for testing specimens of rubber, permitting determination` of the qualities thereof adiabatically as well as isothermally, but it is not confined to such an application,

weighing machines,

being useful for seismograp'hs,

wherein it would effect great commercial saving, and impact; testing machines, such as for ascertaining the blows of a vehicle on a road-bed. These and otherv applications of the invention are ob- "vious, and all uses are comprehended which employ the underlying principles thereof.

, `Embodiments of the invention are illustrated in the accompanying drawings in 1 is a diagrammatic elevation of a machine suitable for testing rubber specimens Fig.- 2 shows stirrups for use in the machine of Fig. l, facilitating compression tests Fig. 3.

shows ainethod of testing specimens in parallel; Fig. 4 shows the application v of the invention to an l air .speed meter;

Fig. 5 illustrates conventionally a seismograph utilizing vthe closed hydraulic system of the present invention Fig. 6 shows an impact testing ap aratus suitable for mounting in a'road-be to enable the shock of avehicle and its rebound to be recorded. l

8.are front and side elevations,

Figs. 7 and lpreferred form. rIhis is illustrated in Fig.4

1, in which is shown a readily'compressible container, indicated generally at 1, having ri'gidj ends 2 and 3, the latter of which is tree andpreierably accessible for the appli- 1 cation of force through al lever or directly to the abutment or surface 4. The sides of the container, as shown, are corrugated, as indicated at 5, to permit of collapsing and thereby changing its volumetric capacity with no error introducing resistance. The material may be copper, phosphor bronze, or in fact any material of a high or low resiliency that will permit the container to yield readily when force is applied to a portion of the walls of the container. l prefer to employ copper, however, as that may be manufactured in the crimped or bellows form illustrated in one piece and circular in cross-section. But the form of the container may be varied, a hollow oblate spheroid, for

'- instance, might be employed for some pur.-

poses, if the range of test pressures is small, without substantial error, or if the range of forces applied to test the specimens be great, correction could be made by suitably calibrating the scale or record sheet.

@ne end of the container 1 is preferably fixed to, or arranged to react against a rigid immovable support, such as indicated at 6. To limit the extent of collapse of the container, plugs 7 may be located internally so as to abut one against the other. Their use,

however, is entirely optional, merely rendering the apparatus safe against the develop ment of la disruptive pressure within the closed hydraulic system. The second element ofy the system is indicated generally at 8. lt comprises essential- 1y a longitudinally bent tube 9, preferably attened in cross-section, as indicated at 10,

having one extremity 1l that is adapted to be anchored or secured in any suitable maw ner to some convenient fixed part and having its other extremity 12 free to move with changes in the fluid pressure in the tube.v vllo the free extremity l12 of the tube, a pointer, mirror, or a scriber, such as indicated at 13, may be attached for indicating or recording l by its deflection force applied to the system.

Connecting the container 1 and the tube 8 is the third element of the system, a-hollow 'mechero conduit 1li, preferably of copper, butv any other suitable material which is 'not expanded bythe pressures to which the system 1s subjected, may be employed. l` he conduit 14 establishes communication between the hollow bent tube 8 andvcontainer 1. lt will be understood, ofcourse, that a liquid, such as alcohol, oil, or water, completely fills the container l, conduit la andA longitudinally curved tube 8, and that the conduit 14 may be as long oras short as desired.

lVhen a force is applied to the accessible abutment; pressureis immediately developed Within the liquid'filling the system exactly proportional to the torce, the area of liquid effectively resisting the same being constant -regardless of any displacement of the end wall of the container. rlihe liquid is incompressible, the conduit la is non-expansible, and the helically coiled tube 8 is the only thing that opposes inward (or outward) dis placement of the end 3 of the container. rlhisf tube 8, however, offers a comparatively high resistance to increase in its volumetric capacity. Upon increase of pressure within the system, the free end 12 of the tube moves or is deflected. lt is believed that this isdue lWhich of thesetendencies ot the tube dominates is not known, and, So far as the invention is concerned, does not seem to be important, for either or both may be` present and utilized. Whatever may be the explanation, an application of say 50 lbs. to the end wall 3 of a container 1-whose area in crosssection is, for instance, 2 sq. ins., and which consequently develops aA pressure within the system of 25 lbs. per sq. in.-produces a full scale deflection of the pointer 13, the free end 12 of the tube moving' about 3A; or 1/2 of an inch. ln this example, the application of 50 lbs. pressure to the end 3. produces no visible, or .a negligible, movement thereof and consequently, the volumetric change in the tube 8 is veryV small despite the appreciable movement of the free end 12 of the curled tube. Instantly the pressure is rcmoved from the end 3 of the container 1. the pointer 13 on the free end 1 2 moves back to its starting position. rlhe restoring force is primarily, and practically entirely, that iuherent in the elastic structure of the Bourdon tube 8. rllle volumetric decrease in the container 1 and increase in the tube 8, in this illustration case, are not more than a few drops of the liquid and thedisplacen'ient ot the abutment a is only a few tho'usan'dths ot an inch. lt will ybe understood in the-fiore going that reference is made to a particular' size of container and Bourdon tube and that the figures are given merely for the purpose l 'of making the disclosure clear and definite,

lle

-' shown diagrammatically as it may be employed in an elemental form for testing rubber. A specimen l of rubber, for instance,

may be positioned between two jaws 16 and 17 to the latter of-v which a'pull may be app1ied^through a slidable rod 18 and handle 19, and thereby the rubber specimen 15 stretched with a force which is measured through the upper jaw 16. For this measuring, the upper jaw 16 may be connected to one end of a lever 20 fulcrumed at 21,

whose opposite end 22 is adapted to press against the abutment 4 and thereby raise the pressure within the fluid system to a degree depending upon the effective internal cross-section of the" container 1 and the loca-- tion of the fulcrum 21 with respect to the ends ofthelever 20. y

In the plane of movement of lthe free end of the marker 13, is located a chart 23 suitably mounted in a frame 24 reciprocable i-n guideways 25 and substantially balanced with a counterweight 26 connected thereto by a cord 27 which passes over a pulley 28. To the lower end of the frame 24 is connected an inextensible cord or wire 29 which is secured to the pull arm 19 by which the .l stretched., 1

. swiped across'thechart at a substantial'an-v specimen ofrubber is adapted to be In operation, Lwhen the specimen 15 is stretched by a force applied thereto through the arml 19,.the.chart23 is displaced in one direction'exactly jas much asthe specimen is. stretched vwhile v simultaneously through the-fluid system 1--14- 8, the marker'13 1s gle. The apparatus above described is exceedingly simple 'and accurate, enables the hysteresis of rubber compounds to bev .de-r

terminedaccurately'and either adiabatically or istherinally, the former being possible because 'of the instantaneous responsiveness of the fluid pressure system. vNetitwithstanding the emp' oyment of ductile andrelatively v 1 inelastic metals, suchv as copper or brass, for the container 1 and coll v8"-these materials being preferable for manufacture, but others may be employed-fall parts ofthe apparatus are well within' their elastic limits and consequently, obey Hookes law. The de- 21 so as to vary the leverage, by employing a container-or sylphon, as it is known on the market-of a suitable size in cross-section and by utilizing a longitudinally curved tube 9, oflering greater or lesser resistance to an internally applied' pressure, the apparatus may be adapted to handle or test a wide variety of substances, if not any and all materials.

For testing rubber in compression, the jaws 16 and 17 of Fig. 1 may be replaced by stirrups 30 and 31, Fig. 2.\

In Fig. 3 of the drawings' is illustrated another method of testing rubber specimens 15. In this, 4the specimens are arranged parallel andare connected to the opposite ends of a lever 32' and pull-rod 33. If the specimens are of identical cross-section, the lever 32 may be fulcrumed at, 34.- midway its effective length. If the specimens differ in thickness or gage, 'the arms ofthe lever may.

so f

be varied in length to compensate therefor.

In either-4A case, however, differences in the properties offthespecimens only are indicated or recorded, the extent of displacement of the pointer 13 being made anything desired by locating the -extremity 4 of the container `or sylphon 1 a greater or lesser distance from the fulcrum 34. This parallel arrangement for testing rubberJ is highly desirable for some .purposes as-specime-ns are usually stamped outlwitha die so that they yare of the same dimensions in'4 one plane, but fre,-

' qnently vary in gage or thickness at right angles to said plane. This parallel arrangement permits oftaking at one and the same time, a tension and compression test. It allows also of a greatincreasein sensitiveness as differences in the'specimens only are indicated and as the amplitude or displacement of the pointer 13 may be multiplied as desired merely shifting the end 4 of the sylphon away from the fulcrum. Of course,

the container or sylphonl is connected up to a BourdontubevS, in this application of vthe invention, as has already been described in detail.

In Fig. lof the drawings, tbeclosed elastic frictionl'e'ss hydraulic system is shown diagrammatically as it may be utilized in an air speed meter for airplanes or observation purposes. As therein illustrated, it comprises avane or extensive surface 35 on an arm which is hinged at. 36 and adapted intermediately, as at 37, to apply a force to the shiftable end ofthe collapsible 'container 1 forming part of' the hydraulic` system 114-8, 'and thereby develop a pressure within the same.

Fig. 5 lof the drawings illustrate still another application of the invention in which the closed hydraulic system 1-14-8 has its freely movable extremity l loaded with Aa.'

dead weight 38 -freely responsive to shocks frictionless confinement in a housing or stuffing box 39. In this forms 1t constitutes a seismograph for recording shocks either within the surface of, the earth or on a travelling vehicle or for recording stresses produced by changes in the direction o f travel of an airplane.

An impact testing machine, illustrated in Fig. 6 of the drawings, is still another form in which the invention may be utilized with advantage. Heretofore, shocks on a road from a travelling vehicle have been ascertained by -computation from the extent4 of'compression of a copper cylinder. With my invention, a suitable number of sylphons 1, preferably three or more, may be imbedded inxa roadway and covered with l la plate or'platform 40 upon which a vehicle may be dropped from a suitable height, as indicated at 41, while passing along a road in the direction of the arrow. The lseveral sylphons are .in communication withone another and with a conduit 14 connected upto a hollow coil 8 of the previously described construction and located off to one side out of the way of the vehicle. lVhile only onesylphon may be employed, a number of them are referred in order to stand a force of'many thousand pounds.

If .not already understood, it is to be noted that the sylphons or container elements of theclosed hydraulic systems `may be made of double or triple wall thickness to withstand a high pressure, of say 100 lbs. per

n square inch, and of almost any diametern each having a large effective area, of say about 100 square inches. A gage or coil tube 8 of the previously indicated capacity placed in communication with such a largel chine are substantially the same as those previously mentioned in connection with the description ofthe machdne diagrammatically illustrated in Fig. 1 of the drawings. 'Ihis commercial form of vmachine of Figs.

. 7-10, inclusive, will therefore now vbe described primaril to disclose its details of construction an certain practical advantages of the closed hydraulic system will be emphasized.

Referring to Figs. 7-10 of the drawings, the commerciallmachine is shown as comprising an upright frame 50, at the top of which is an overhanging bracket 51, fashioned at its front with a substantially. lonnected lto a slide 58. And slides 59 and 60 are also mounted on the lever 57. Each of.

the slides 56, 58, 59 and 60, is preferably provided with a thumb-screw 61 for turning a pinion 62 journalled therein, the pinion 62 being adapted to engage a rack 63 rigid with thelever 57 `By turning the thumbscrew 61, the several slides may be adjusted lengthwise of the lever. A locking nut 64 is also provided on each of theslides to secure them in an adjusted position. Inextensible strips or bars 65 depend from each of the slides 59 and 60, and to the lower end of each of these, gripping jaws or specimen holders 66, of any ,suitable form, may be attached to carry the load applied to a specimen to the lever 57. Only one jaw is shown as the other is used for a special purpose to be described later.V

'Ihc incompressibility of the fluid in the hydraulic system, of which the sylphon 1 is a part, permitting no-or a negligiblelnotion of the lever 57 in operation, the lower end of the sylphon 1 may be positively connected to the slide 58, which I prefer to do. The lower end of the sylphon 1 may, however, be placed in abuttingy relation, and not connected, with the lever 57. The sylphon 1 is connected by a conduit 14 with a Bourdon gage 8q or other form of element made highly resistant to change in its volumetric capacity that may he employed. The gage 8 is shown secured by brackets 67 to the top-68 of a'housing 69 at the'bottom of and rigid with the frame 50. One end of the coil tube 8 is anchored and theother end free. The free end carries alight flexible ,Strip 70, terminating in a marker 71, which is adapted to be moved approximately in the arc of a circle in a direction more or less horizontal. Beneath the marker 71 is located a record carrier 72, preferably in the form of a board, with pinch-clamps 73 at its margins for ready mounting of 'a record sheet, spring clips 74 normally maintaining the grip of the clamps on a sheet of co-ordinate paper.

'Ihe recordcarrier 72 may be connected positively with the lower specimen gripper 66"7 so as to be moved exactly to the same extent as the specimen is deformedthat is, elongated or shortened-but I prefer to provide a means permitting a 1:1, 1:2, or 1:5, movement of the lower jaw-66' relative to the `record carrier 72. 'Io this end', the pull-rod 75, which is directly connected to the lower jaw 66 and by which the specie men is stressed, is provided on one side withgpll.

location of the grooves. The opposite end of the shaft 77 is journalled in a sleeve 80 which is suitably bushed in portions ofthe housing 69. Keyed ko'n-'the shaft 77 are three different sized pinions 81, 82 and 85, vwhich co-operate with gears 81', 82 and 85 on a shaft 86, carrying a pinion 87 engaging a second rack-bar 88 parallel to the pull-rack 75. Theraek-bar-SS-is connected to the record carrier 72. By suitable selection of the gears 81-82-83 to intermesh with one of the primed set, the record carrier 72 maybe moved to the same extent, or half or onelifth the extent, the specimen is deformed by a7stress applied to it through the rack- Stress( may be a plied to the specimen Athrough the lower'jaw 66 either by power or by hand. For power operation of the machine, a'belt is aplpplied to a pulley7 -89 on a stub-'shaft 90, w ich is parallel to the shafts 86` and 77. By pinion 91"keyedto shaft 90, the power may be ltransmitted through a gear 92,. which is rigid with a sleeve 93 fashioned intermediately' with a pinion 94, to a ear 95 that is keyed to the,

before-mentione sleeve 80. The sleeve 80 is fashioned interm'ediately to form a pinion 96 engaging a gear 97 on a fourth shaft 98 having a pinion portion 99 engaging a second rack formed on the pull-bar 75. Thus', by power, the pull-rack 75 may be actuated to stress a specimen and by suitable endwise adjustment of the shaft 77 lmade to simultaneously move the record carrier`72 to the desired extent in proporltion to the deformationof the s ecimen.

For accomplishing the same en manually by power, the shaft 98 may be shifted endwise so as to disengage its gear 97 from the power ,train and allow of its independent rotation by a hand-crank 100, which is detachably secured, as indicated at 101, to the squared end ofthe shaft. A keeper 102, similar to 79, reviously described, may be utilized vto lioldp the shaft 98 against endwise movement in either of its positions.

'- v Itis often desirable to make a number record carrierso as to separate the 'hysteresis loops'or diagrams. To space the loops apart, I preferably attach to the back of the record carrier, a pl'ate103 lcarrying a And consequently, itis of at vantage to be able to readily shift theA rotatable pinion 104: which is engaged with the rack formed on the bar 88. To resist rotation of the pinion 104, I ,provide a spring detent 1.05 which ligntly engages its teeth in such a way as to permit the application of a livht force to the record carrier 72 to cause the detent Ato be overcome and` thel board to be shifted up or down a disy `tance equal to the pitch of the rack teeth (or a. multiple thereof).

In the'commercial form of testing machine of Figs. 7-10, inclusive, a great ractical advantage `of' my closed liydraulimsystem is disclosed. This s stem enables me to use a strip lsuspension or the lever, which type of suspension as is well-known has far less friction than a knife edge. I am enl abled to use a strip of steel or other metal to suspendthe leversince there is practically no motion or movement of thev latter in operation. The suspending strip may, therefore, be made of considerable stiffness with;- out introducing an error in the measurements. Owing to the fact that the lever '57 is substantially stationary, I may also, without ei'ror, secure the bottom or shiftable end of the sylphon 1 to the lever, and thus obtain an organization whose vital part, the closed hydraulic system, neednot be tampered with b an operator and which it would be di cult` for him to get outl of order. In other words, the organized machine is not delicate, being, as a matter of fact, almost foolproof. In this commercial form of testing machine, the force applied to the specimen is measured by the motion of the free end 12 of the gage 8, the motion thereof being `exactly proportional to the vforce applied to the specimen. That is to lresides primarily in the coil tube 8 which is highly resistant to deformation. But there is some elastic resistance to the force applied to the specimen in the elastic container or sylphon l1 and in the el stic strip suspension 55. It is a valuable feature of the present invention that all the elastic reactions to the applied force may be divided in any proportion between the longitudinally benttube 8,;the elastic'container or sylphon 1 and the resilient strip suspension 55,

and kthat they may be of any convenient amount. In every case known, the deflection is directly proportional to thecforce applied to the specimen because well. within the elastic limits of the materials,

The adjustabilty of the lever 57 in the commercial form of machine illustrated in Figs; 7-10, inclusive, permits of testing `.specimens in parallel, as diagrammatically n illustrated in Fig. 3. For this purpose, the` strip suspension 55 is moved to a position' in line with the pull-rack 75 and a second jaw is attached to the strip or connector at the left end of the lever 57. A Llli-bar, not shown, is then attached to the lower jaw G6 and, two specimens mounted inI place as diagrammatically'illustrated in Fig. 3.

The commercial testing machine not only permits testing in parallel, but generally, stress and strain records, hysteresis loopsY and breaks may be conveniently and quickly 'made and recorded with any kind of stock and with any degree of stretch. Other features of the commercial form of testing machine illustrated are that manual as well as power operation is provided for in the two lines of transmission or trains of connections for reciprocating the rackbar 75. The hand operation may be performed very rapidi and thereby adiabatic tests promptly obtained. rlhe adjustability range of resistance.

of the head of the machine, particularly of the sylphon 1 and suspension strip 55, as well as the slides on the lever 57, permit of arranging the apparatus for testing any kind of stock and, therefore, of determining the characteristics of specimens over a wide llt is also to be noted that the closed hydraulic system 1-14-8 may be readily replacedl by .another ofgreat- 3C er or lesser stren th, as the need may be, to

convert the machine over for testing entirely diiferent materials, it being obviously immaterial in the operation of the machine what degree of stress is applied to a specimen so long as it does not exceed the strength ofthe materials transmitting the force applied to the closed hydraulic system.

While no difiiculty has been encountered in setting the indicator 13 to a zero position, this maybeaccomplished, if desired, in a varietyT of Ways as, for instance, by adjusting a weight (not shown) more or less away from the fulcrum of the lever 57 or by adjusting a s ring (not shown) opposing movement o the lever 57. The paper on the record carrier may also be shifted alittle to obtain a convenient zero position. By local constriction of the conduit 14, the pointer 13 maybedampened. -The closed hydraulicsystem is practicall unaffected by changes in temperature as t ie syl )hon 1 takes up any change in the volume of t e sys- 'tem without any appreciable movement of the, indicator 13.

In the foregoing. I have endeavored to 'set `:forth fully the principles underlying my invention and to show not only its scope by illustrations of various applicationsthercof but also its practical advantages by a. dis-l closure of a specific commercial form'of testing machine. ,The invention has great conimercial advantages some of which have been pointed out vand others of which will be apparent-to thosewskilled in the art. All advantages inherent in the system are compreessere hcnded however and all changes in details ofconstruction not departing from the underlying principles of the invention are intended to be included within 'the annexed claims to which reference is made.

elements constituting the closed hydraulic system may. be widely varied and that a vresistance external of the systcnrmay be employed, if desired, although deemed less preferable than that which inheres in the system, particularly the wall structure of the coiled tube 8 or its equivalent.

Having thus described my invention, what l claim and desire to protect by Letters Patent is:

l. A closed elastic frictionless hydraulic system for determining forces applied in testing machines through pressure produced by the forces in the system including in combination, a unitary container with longitudinally collapsible peripherally instantiallyrigid` end walls, a curved elastic tubular member having an anchored porlt will be obvious, for instance, that the form of the f extensible side walls and freely shiftable sub- ,y

tion and an extremity movable in direct proportion to the change of pressure within the system, and a conduit establishing communication between 'the container and the curved tubular member, the liquid filling the conduit being substantially limmovable throughout the range of operation of the system.

2. A closed elastic4 frictionless hydraulic system for testing machines including in combination, a unitary container with rigid end Walls and peripherally inextensible side walls of a freely collapsible formation substantially non-resistant to change in its volumetric capacity, an elastic device highly resistant to change in its volumetric capacity, and a non-eXpansible conduit connectlli-3 ing the container and device, ,the liquid fillcombination, a unitary container with rigidl end walls and peripherally inextensible sid(` Walls of a freely collapsible formation substantiall)v non-resistantto change in its volumetric capacity, "an elastic hollow device highly resistant to volumetric change. said device having a portion immovably anchored and another portion free to move with varia- `tions of pressure within the hydraulic system, and a non-expansible conduit connecting the containery and hollow device. the liquid fillingthe, conduit being substantially immovable throughout the range ot operation of the system.v

v4. A closed elastic frictiouless h vdraulhl system for testing machines including in combination. a unitary container with rigid end walls and. eripherally ine-Xtensible side AWalhi of a lfree y collapsible formation substantially non-resistant to volumetric change, anelastic hollow device highly resistant to volumetric change, said device having an extremityfree to move Witlrvalriationsvin pressure. within the hydraulic system and self-restorative when the external ressure does not strain the material of the evice beyond its elastic limit, anda nonexpansible conduit connecting the container and device, the liquid filling the conduit .being substantially immovable throughout llongitudinally bent ..elastic tube highly resistant to volumetric change, said tube bcing anchored at one point and free to move at another the free portion of said tube bcing movable in direct proportion to changes of'pressure Within the elastic limit of the materialv of the tube, and a substantially non-distensible conduit connecting the container and the longitudinally benttube, the liquid'lling the conduit being substantially immovable throughout the range of operation of the system.

6. The combination with an abutment to which forces may be applied and an indieating member of, an intermediate hydraulic motion multiplying system comprising a unitary container laterally non-expansible and without errorroducing frictional resistance, an elastic evice highly resistant to increase in itsv volumetric capacity and having a portion free to move With changes in the pressure Within the system, a non-expansible conduit connecting lthe container and device, said container being rigidly connected with said abutment, and the free portion of said device being directly connected withv said indicating member,y the liquid filling the conduit being substantially immovablethroughout the range of operation of the system.

7, Thevcombination with an abutment to which forces may be applied and an indicatingmeihber'of, a unitary container withcollapsible but Ainextensible side Walls, a

curled' tube adapted to be anchorediatone end and vfree' to move at the other, a noncxpansible conduit connecting the container and the curled tube, said container being rigidly connected with` saidabutment and the free end of the curved `tube being direct- I ly connected with the indicating member, the liquid filling the conduit being substantially immovable throughout the range of opera-- tion of the system.

lrange of operation ofthe system.

9. A closed elastic frictionless hydraulic system for testing machines including in' combination, aunitary containerivith rigid end Walls 'and collapsible peripherally inextensible side Walls hermetically connected together, a'device highly resistant to volu, metric change and having' a portion movable substantially and appreciably when the lV01-,

uinetric change is minute and ina-ppreciable,

and a conduit connecting said container andy device, the liquid filling the conduit being substantially immovable throughout the range of operation of'the system.

lil). A closed elastic frictionless hydraulic system for testing machines including in combination, a unitary container with rigid end Walls and collapsible pcripherally inex- Vtensible sidewalls hermetically connected together. a. hollow motion-multiplying-device highly resistantto increase .in its volume' and vhaving a portion or Wall movable to al substantial extent with variations in pressure within the system, and a conduit connectingy said container and device. the liquid filling the conduit beingi substantially"'imi'novablc throughout the range of operation of the system. v

11. A closed elastic vfrictionless hydraulic system for testing machines including in combination, a unitarv container with rigid end Walls andcollapsible peripherally inextensible side walls hermetically connected together, a hollow elasticdevice with a movable end or Wall portion and constructed to oier a 'high resistance to increase in its volume, and a. conduit connecting the con-vv tainer andhollow device, the volume of the system thereby constituted being substantially constant in operationythe liquid filling the conduit being substantially immovablel throughout the range of onerationl of the system.

12. vA closed elastiefrictionless hydraulic system' including a unitary containerwith rigid end walls and .collapsible p'erinherall)v inextensible side. walls hermetic-ally con vnected together, a hollow device vwith an end Wall movable by variation in ypressure there-y within, a conduit connecting saidcontamer and hollow device` in combination with. a

frame, a lever, and means for stressing the specimen and through it pulling uponthe v12ol y and hollow device. in combination with, a

framega lever, and means for stressing the specimen and through it pulling upon thev lever, said ycontainer being collapsibly and' a-djustably confined between said frame and said lever.

14. A closed elastic `frictionless hydraulicv system including a unitary container with rigid end walls and collapsible peripherally inextensible side walls hermetically connected together, a hollow device with an end wall,

movable by variation in pressure therewithin, a conduit connecting said container and hollow device, in combination with, a frame, a4 lever, a strip suspension for said lever, and means for stressing the specimen and through it pulling upon the lever, said Y container being collapsibly con tined between said frame and s aid lever. l

15. 'A closed elastic frictionless hydraulic system including a unitary container with rigid end walls and collapsible peripherally inextensible side walls hermetically connected together, a hollow device with an end wall movable by variation in pressure there'- within, a conduitl connecting said container and hollow device, in combination with, a trame, a lever, a strip suspension for said lever, and means for stressing the specimen and through it pulling upon the lever, said container being collapsibly confined between said frame and said lever, and said strip suspension and said container being adjustable relative the frame. v

1G. A closed elastic frictionless hydraulic system including a` unitary container with rigid end walls and collapsible,peripherally inextensible side walls hermetically connected togetherJ a hollow device with anend wall movable by `variation in pressure therewithin, a conduit. connecting said container and hollow device, in combination with, a traine,

a lever, a strip suspension for said lever. and means for stressing the specimen and through it pulling u )on the lever. said container being collapsibly confined between said frame and said lever, and said strip suspension and said container being adjustably connected to said lever whereby to pei'- vmit variation in theleverageariiis thereof.

" 17. A closed elastic frictionless hydraulic system including a unitary container with rigid end walls and collapsible peripherally and hollow device inextensible side walls hermetically connected together, a hollow device with an end wall movable by variation in pressure therewithin, a conduit connecting said container traine, a lever, an means for stressing the specimen and through it pulling. upon the lever, said container being collapsibly confined between said frame and said lever, said last named means yincluding connections permitting the specimen tobe stressed selectively either mechanically or manu-ally.

18. A closed elastic frictionless hydraulic system including a unitary container with rigid end `walls and collapsible peri hcrally inextensible side walls hermetic-a ly connected together, a hollow device with an end wall movable by variation in pressure therewithin, a conduit connecting said container and hollow device, in combination with, a trame, a lever, and means for stressing the specimen and through it pullingA upon the lever, said container being collapsibly con fined between said frame and said lever, said closed hydraulic system being demountable and replaceable by another of different 09.-.

pacity without substantial change in the re-l lation between the lever and the frame, the liquid filling the conduit being substantially immovable throughout the range ot operation of the system.

19. A closed elastic rictionless hydraulic system including a unitary container with rigid end walls land collapsible peripherally inextensible side walls hermetically connected together, a hollw device with an end wall movable by variation in pressure therewithin, a conduit connecting said container and 'hollow device, in combination with a frame, a lever, and means for stressing the Specimen and through it pulling upon the lever, said container being collapsibly confined between said frame and said lever, and a record' carrier movable in proportion to and simultaneously with the means for stressing a specimen, the liquid filling the conduit being substantially immovable throughout the range ot operation ot the system.

20. A closed elastic frictionless hydraulic system including a unitary container with rigid end walls and collapsible peripherally vinextensible sidewalls heiinetically connected together, a hollow device with an end wall movable by variation in pressure therewithin, a conduit connecting said container and hollow device, in combination with, a frame, a lever, and means for stressing the specimen and through it pulling upon the lever, said container being collapsibly conlined between said frame and said lever, and connections between the record carrier and the means tor stressing the specimen permitting the former-to be moved in various predetermined proportions relative to one end in combination with, a

lll)

of the specimen, the liquid filling-the conduit being substantially immovable throughout the range of operation of the system.

21. In a testing machine, a closed elastic frictionless4 hydraulic system comprising a unitary container with rigid end walls and collapsible peripherally inextensible side walls, a longitudinally bent hollow tube, a conduit connecting the container and tube, said conduit, container and tube being filled with liquid, in combination with a le ver operatively associate'd with the collapsible container, means for connecting a speciy men of material with said lever, means for stressing the specimen of material by enp9 gagement of the' other end thereof, and means for simultaneously recording stresses and 'deformation of the specimen, the liquid filling the conduit being substantially immovable throughout the range of operation ofl the system.

22. In a testing machine, a closed elastic frictionless hydraulicvsyste'm comprising a said conduit, container and tube being filled with liquid, in combination with a lever operatively associated with the collapsible container, means :for connecting a specimen of material with said lever, means for stressing .the specimen of material by Vengagement of the other end thereof, and means for simultaneously recording stresses and deformations of the specimen, said lever being susnded by a lstrip of resilient material, the liquid lling the conduit being substantially immovable throughout the range of opera-y tion of the system. f

' Signed at New York, county of' New ',York, and State of New York, this 31st day of August, 1922.` c

JOSEPH G, COFFIN. 

